hpux man page for xtinputcallbackproc

XtInputCallbackProc()													     XtInputCallbackProc()

Name
  XtInputCallbackProc - interface definition for procedure to handle file, pipe, or socket activity.

Synopsis
  typedef void (*XtInputCallbackProc)(XtPointer, int *, XtInputId *);
	  XtPointer client_data;      int *source;	XtInputId *id;

Inputs
  client_data
	    Specifies the data that was registered with this procedure in XtAppAddInput().

  source    Specifies the file descriptor (on POSIX systems) that generated the event.

  id	    Specifies the ID that was returned when this procedure was registered with XtAppAddInput() call.

Description
  An  XtInputCallbackProc  is  registered  with  XtAppAddInput().  It is called when there is activity of the specified type (read, write, or
  error) on a specified file descriptor (which can be a file, pipe, or socket).

  An XtInputCallbackProc should do whatever is necessary to handle the activity on the alternate  event  source.   If  EOF  is	read  on  the
  descriptor, the procedure can un-register itself by passing its id argument to XtRemoveInput().

Usage
  An  XtInputCallbackProc  is  inherently operating-system-dependent and will have to be ported when the widget or application is ported to a
  new operating system.  On non-POSIX systems, the source argument is some OS-dependent identifier of an input source.

Example
  The procedure below is an XtInputCallbackProc from the xconsole client (which is new in X11R5).  Note that it reads input  with  the	POSIX
  read()  system  call,  and  that it closes the file descriptor and removes the input source if it reaches EOF or gets an error on the input
  source.

     static void inputReady (w, source, id)
	 XtPointer   w;
	 int	     *source;
	 XtInputId   *id;
     {
	 char	 buffer[1025];
	 int	 n;

	 n = read (*source, buffer, sizeof (buffer) - 1);
	 if (n <= 0)
	 {
	     fclose (input);
	     XtRemoveInput (*id);
	 }
	 Notify ();
	 buffer[n] = ' ';
	 if (app_resources.stripNonprint)
	 {
	     stripNonprint (buffer);
	     n = strlen (buffer);
	 }
	 TextAppend ((Widget) text, buffer, n);
     }

  This procedure is registered with the following call:

	 input_id = XtAddInput (fileno (input), (XtPointer) XtInputReadMask,
				inputReady, (XtPointer) text);

See Also
  XtAppAddInput(1), XtRemoveInput(1).

Xt - Event Handling													     XtInputCallbackProc()